The present invention relates to a die-casting mold for a brake master cylinder housing and a brake master cylinder housing manufactured by this mold which contains an axial master cylinder piston bore and a compensating bore, whose latter axis extends parallel to the axis of the master cylinder piston bore. The compensating bore has one end terminating in a compensating reservoir port that is oriented transversely relative to the housing's longitudinal axis and its other end terminating in a sealing chamber that is formed by an extension of the master cylinder piston bore.
From German Patent DE-OS No. 3,021,893, there is known a brake master cylinder housing comprising an axial master cylinder piston bore and a compensating bore whose latter axis extends parallel to the axis of the master cylinder piston bore. In this brake master cylinder housing, the compensating bore is constructed as a stepped bore, with the portion of the bore of smaller diameter terminating in the compensating reservoir port and the portion of larger diameter terminating in a sealing chamber.
When constructing the housing in this fashion, various problems will be encountered, particularly when the housing is constructed as a die-cast housing, for reasons of manufacture. Due to the stepped shape of the wall of the compensating bore, a draft angle can be manufactured only by retrospective drilling of the compensating bore. Besides, it is not possible without difficulty to provide for a sufficiently stable core necessary for the molding process, since it must be ensured that sufficient wall thickness is maintained in the area of the reservoir port because the pressure discharge ports are also arranged in this area.